Fiberglass devices are manufactured utilizing a number of techniques. For example, in one technique a structure is built up by spraying chipped fiberglass roving and resin together onto a mold having the desired configuration. In another, more recent, process fiberglass roving and/or mats are continuously drawn through a resin bath and the combination of fiberglass and resin is compressed and heated in a forming die. A continuous process is thus provided for the production of a laminated fiberglass-resin structure. The process, which can be called pultrusion (in distinction from extrusion), is particularly well adapted for the production of continuous lengths of board which are substantially longer than wide and substantially wider than thick. Such boards have a number of utilities, a popular utility being for the formation of skateboards and of surfboards, each of which require a high degree of rigidity yet also require a thin, elongate form. Such boards are also made by compression molding, and, in fact, until the present invention, the latter process provided a number of advantages over continuous processes in its ability to enable indicia to be imprinted directly into the outer surface of the laminated structure.
I have now discovered a method for operating a continuous pultrusion process so that it provides additional advantages not heretofore obtainable with such process. Specifically, I have now discovered a method by which a fiberglass-resin laminate can be continuously formed with a permanent pattern of indicia thereon. In one embodiment, the indicia is in the form of printing or the like submerged beneath an external surface of the laminate and visible through the resin. In another embodiment, the process enables a pattern of indicia to be imprinted in intaglio form into the outer surface of a laminated structure.
More specifically, a multilayer of fiberglass, formed of elongate rows of roving and/or fiberglass mat, is continuously passed through a reservoir of resin therefor to thereby obtain combination of the resin with the fiberglass. A support member having a continuous elongate sheet form, and bearing the pattern of indicia, is disposed in alignment with and adjacent the outermost layer of the fiberglass. The combination of fiberglass and resin and the aligned support member are drawn together through a die having internal opposing surfaces which are spaced sufficiently close one to the other to substantially compress together the support member, fiberglass and resin, and the die is heated sufficiently to at least partially cure the resin whereby, upon cooling, a self-supporting, unitary, elongate laminated structure is obtained having a permanent pattern of the indicia visible thereon below the plane of an external surface of the laminate.
The process includes a number of embodiments in which the indicia is provided as a pattern submerged beneath an external surface of the laminate. In this regard, the support member can comprise a sheet, such as a sheet of cloth, carrying the indicia as a printed pattern thereon. In another embodiment, the indicia is carried on a potentially transparent support member, such as paper, which when subjected to the heat of the die impregnates and disappears leaving the indicia visible.
In a further embodiment, the support member is in the form of a transparent polymer material and in this regard the indicia can be printed in reverse on the bottom surface of such material or can be printed on a second layer or coating of organic polymer material aligned therewith and disposed therebeneath. In the latter embodiment, the second layer can be formed of such material as polyvinylidene chloride while the first polymer sheet is formed of a material, such as a terephthalate polyester, having poor adhesion therefor. After the laminate has been drawn through the forming die and cooled somewhat, upon removal of the terephthalate polyester, a smooth glossy surface is provided, enhancing the appearance of the product.
In still another embodiment, a top layer of fiberglass mat constitutes the support member and is directly imprinted with the desired indicia, or a discontinuous series of flat members are disposed thereon, each member being sufficiently thick so as to leave, when removed, an intaglio pattern.
Other aspects of the present invention will be understandable as the invention is described in more detail hereinafter. A result of the process is the creation, as a unique product, of a self-supporting, elongate, structure comprising a unitary laminate of a plurality of layers of fiberglass and resin and formed with a permanent pattern of visible indicia submerged beneath an external surface thereof.